The measurement of rotating speed or rotation angle, detection of position, etc. have employed reluctance type resolvers or variable reluctance type resolvers (see, for example, Patent Documents 1 and 2).
In such reluctance type resolvers, there is incorporated a variant-shaped laminated core 60 as shown in FIG. 6 in which are laminated core sheets of plural different types as regards the outer shape or size (core sheets of each of the types form a respective one of first to third laminated bodies 61 to 63 for example). Examples of variant-shaped laminated cores each comprising core sheets of different outer shapes include a variant-shaped laminated core formed by laminated core sheets having off-centered shaft holes.
For accuracy improvement in the measurement of rotating speed or rotational angle and in detection of position with use of the variant-shaped laminated core 60, it is required that the core sheets are firmly integrated. For this reason, in the production of the variant-shaped laminated core 60, the core sheets are laminated and interlocked by caulking portions 64. Note that in FIG. 6, reference numeral 65 denotes a shaft hole.
A single press die device punches out core sheets of the same outer shape. In the case of punching out of core sheets of plural different types as regards the outer shape or size, press die device types need to be replaced for adaptation to the type of core sheets to be punched out.
Further, also in the case where plural types of core sheets are punched out, then laminated and interlocked, the changing of press die device types is needed to punch out core sheets of different types, which lowers productivity.
To solve this problem, a technique as shown in FIG. 7 has been employed. This technique is by: punching out one type of core sheets successively using a press die device of the type corresponding to the type of the core sheets punched out; laminating the punched out core sheets to a thickness greater than required for use in a single variant-shaped laminated core thereby to form a successive lamination; taking out, from the successive lamination, a portion (a lamination unit) to be integrated in a variant-shaped laminated core; and combining the lamination unit with lamination units of other core sheet types that have been taken out in the same manner.
[Patent Document 1]    Japanese Unexamined Patent Application Publication No. 2002-39794
[Patent Document 2]    Japanese Unexamined Patent Application Publication No. 2005-164486